Ultraviolet radiation has been successfully used in the purification (e.g., sterilization) of various media, such as air, water, and food. In general, it is desirable that the ultraviolet radiation comprises wavelength(s) that are close to the absorption peak(s) of biologically significant molecules of DNA and/or proteins of a target impurity. For example, impurities, such as a bacterium, a virus, a protozoan, a germ, etc., comprise DNA/proteins having corresponding absorption peaks. By exposing the DNA/proteins to ultraviolet radiation having a wavelength close to the absorption peak(s) for a sufficient time and at a sufficient power, the impurity is destroyed. To this extent, exposing a medium that includes one or more of these impurities to sufficient ultraviolet radiation can destroy some or all of the impurities. When sufficient impurities are destroyed, the medium is purified to a safe condition.
Various approaches have incorporated different sources for the ultraviolet radiation. To this extent, previous approaches have proposed the use of a mercury lamp, an ultraviolet diode, and/or an ultraviolet laser diode for generating the ultraviolet radiation. Additionally, various approaches have proposed the use of mirrors, a serpentine path, and/or many ultraviolet radiation sources disposed throughout a region to help ensure that a sufficient amount of ultraviolet radiation is provided throughout an area including a flowing medium.